The present invention concerns a bicycle on-board device and more specifically it concerns a device configured to be inserted inside the bicycle frame, as well as a method for mounting it.
Such a bicycle device can be of the stand-alone type or it can be part of an on-board electronic system comprising other electronic and/or electromechanical devices connected by cables or wirelessly.
Bicycle on-board electronic systems are known and are becoming increasingly sophisticated. The on-board device or the system that it is part of can, for example, be intended for controlling and/or managing the gearshift and/or for acquiring, processing and/or storing parameters and/or data relative to the cyclist and/or to the bicycle and/or to the trip. The on-board device or the system that it is part of can also be intended for mobile telephone communication, for multimediality and/or for anti-theft surveillance of the bicycle.
The bicycle on-board device can also merely comprise a battery power supply unit, possibly with associated power supply electronics, for other devices of the on-board electronic system.
US 2001/0042767 A1 and EP 1 553 012 A1 each describe a containment unit for an electronic system for controlling/powering at least one on-board electronic device for a bicycle, having a configuration suitable for fastening outside of the frame at the same attachment point as a bottle cage, and preferably with the same fastening means.
US 2005/0280244 A1 describes a bicycle control apparatus that can be mounted in a seat post and more specifically in a seat post that is detachably mounted in the seat tube. According to this document, the seat post, at its lower end opposite the saddle, comprises a circuit mounting structure like for example an internal threading. The control apparatus comprises a tubular housing, that can be inserted in the seat post, as well as a cover at the lower end of the tubular housing. The tubular housing houses a control unit in the form of a microprocessor, and it has an internal threading at the lower end. The cover is shaped like a stepped bolt comprising: a head, equipped with a tool engaging structure and having an outer diameter that is slightly smaller than the inner diameter of the seat post; a first male threaded portion having a diameter that is slightly smaller than the diameter of the head; and a second male threaded portion having a diameter that is slightly smaller than the diameter of the first male threaded portion. The second male threaded portion is screwed into the internal threading of the tubular housing; then the first male threaded portion is screwed into the internal threading of the seat post. In an alternative embodiment, the housing is mounted in the seat post in a different manner. The first male threaded portion of the cover is replaced by a mounting structure comprising a plurality of movable projections in the form of retaining balls slidingly retained in a corresponding plurality of retaining holes and biased radially outwardly by a corresponding plurality of springs. The mounting structure also includes a plurality of stationary projections in the form of rectangular male splines. In the seat post, the circuit mounting structure comprises, instead of the female threading, a plurality of recesses in the form of hemispherical grooves and a plurality of recesses in the form of female splines. This embodiment, with respect to the first, has the advantage of not subjecting the cables to twisting during assembly into the seat post.
Holes are provided in the tubular housing and in the cover, for the passage of cables for data and energy transport, equipped with respective connectors. Holes are similarly provided in the seat post, for the passage of cables, equipped with respective connectors. There can also be a groove in the inner peripheral surface of the seat post or in the outer peripheral surface of the housing, to house the cables that come out from the cover and lead them upwards, for example towards the top tube of the frame.
Such a control apparatus has a series of drawbacks. Indeed, such an apparatus needs the seat post to have a tubular cylinder shape, while bicycle frames and therefore seat posts with a non-circular cross section are increasingly common, mainly for aerodynamic reasons; moreover, such an apparatus requires a substantial alteration of the seat post to make the circuit mounting structure, which moreover adapts poorly to seat posts made of a composite material such as carbon fibre. Moreover, it requires the disconnection of the signal and power cables whenever one wishes to remove the saddle. Furthermore, since it has to fit into the seat post that is in turn sized to fit in the seat tube of the frame, the apparatus necessarily has a small transversal size. Finally, bicycle frames with integrated seat post, for which such an apparatus is not suitable, are increasingly common.